Preliminary tests show that the drug known as Mephaline

Question

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Preliminary tests show that the drug known as Mephaline is useful in treating people experiencing memory loss due to Alzheimer’s disease. These same tests showed that Mephaline did not appear to slow or reverse memory loss in people who experienced memory loss due to a brain injury. There must be something qualitatively different about these two types of memory loss.

Which of the following most strengthens the conclusion in the argument above?

A. Mephaline works by acting on the medial temporal lobes of the brain.

B. The patients who took part in the tests had similar amounts of memory loss prior to the tests.

C. People with Alzheimer’s disease usually have impaired powers of speech.

D. Some of the people being tested were unaware that they were given a drug that was intended to reduce memory loss.

E. The average age of the people tested who had lost memory due to a brain injury was less than the average age of the people with Alzheimer’s disease.

oe to follow

pqhai · Accepted Answer

This question follows a classical  comparison form in CR . Very good question to practice.

The form is: 
 Before: .........(hidden statement)........
After event X: A better/worse than B

Conclusion 1: A and B must be different. 
Conclusion 2: X did make A better/worse than B. 
 
 Assumption:   Before: A and B  were the SAME --OR--  had same starting points. 
 Confirm:  Because: if A = B, after event X, A and B must increase/decrease the same level.

ANALYZE THE STIMULUS:  
Fact: Mephaline is useful in treating people experiencing memory loss due to Alzheimer’s disease. 
Fact: Mephaline did not appear to slow or reverse memory loss in people who experienced memory loss due to a brain injury.
Conclusion: There must be something qualitatively different about these two types of memory loss.

Which of the following most strengthens the conclusion in the argument above?

ANALYZE EACH ANSWER:

A. Mephaline works by acting on the  medial temporal lobes  of the brain.
 Wrong.  Out of scope.

B. The patients who took part in the tests had similar amounts of memory loss prior to the tests.
  Correct.   B confirms that the comparison is VALID. See theories above.

C. People with Alzheimer’s disease usually have  impaired powers of speech. 
 Wrong.  Out of scope.

D. Some of the people being tested were unaware that they were given a drug that was intended to reduce memory loss.
 Wrong.  Does not help.  The fact  that people know or not know they were given that drug does  NOT affect those people's memory loss.

E. The average age of the people tested who had lost memory due to a brain injury was less than the average age of the people with Alzheimer’s disease.
 Wrong.   Weaken the argument.  If those people are in different categories --> the comparison is INVALID.

Hope it helps.

avohden · Answer

Official Explanation

Answer: B   - The conclusion is that there must be something qualitatively different about memory loss due to Alzheimer’s and memory loss due to a brain injury. The evidence is that a drug, Mephaline, worked on only one of these groups. If the people with brain injuries had much greater memory loss prior to the tests, then this quantitative difference could explain why the injured people did not appear to be helped, thus weakening the argument. Choice B, by eliminating this possibility, strengthens the conclusion.

(A) This is irrelevant background information.

(C) This does not provide relevant information. There is no reason to think that the test did not take this fact into account.

(D) This gives us some information about how the tests were conducted, but does not specify whether the people who were unaware of the test were in only one group (which would weaken the argument somewhat, since the test wasn’t “fair”) or in both groups, thus strengthening the legitimacy of the experiment, and to some extent, the argument).

(E) If anything, this weakens the argument, since the memory loss difference between the two groups might have been because of their ages, not because of an intrinsic difference between the types of memory loss.

vietmoi999 · Answer

Ron said that we should not alway prethink an assumption and then find strengthener/weakener because this make the question harder because naturally we can find out strengtherner/weakener more easy than an assumption.

if we categorize the arguments into many pattern and find out assumptions for each pattern, we may fall into a trap of memorizing the rules. gmat dose not award the memorising of rules.

I can go to B without prethinking an assumption . if I prethink an assumption, I feel harder and spend more times. and , honestly, in the test room ,we hardly remember "comparision" argument to do some thing.

in short, the approach by learning and memorizing the "comparison" argument dose not work.

that is my idea. pls, comment.

rltw · Answer

B.

Question type: strengthen conclusion
Conclusion: Brain damage and alzheimers affect memory differently.

working from wrong to right (eliminate answer choices and see what's left over):

A) not relevant. not an assumption or fact that further supports the conclusion.
B) this fact establishes that both sets of patients were "equal" at the start of the experiment. drugs effects can be measured accurately since you can now compare both groups of patients (validity). don't cross this one out, but maybe there's a better answer in here...
C) speech has nothing to do with the conclusion (out of scope).
D) this one is a stretch/trick. shows that the experiment followed good scientific practices...however, it doesn't really have anything to do with the conclusion.
E) age has nothing to do with the conclusion.

B is left over. And it is the answer. Yay.

rltw · Answer

vietmoi999-
I haven't watched that video, but I guess what you're saying makes sense. With the strengthen/weaken conclusion questions I deconstruct the argument first to find the conclusion. Then I compare the answer choices to see which fact would support the conclusion. Brainstorming ("prethinking") assumptions could be a waste of time because you're trying to find NEW evidence to support/weaken the conclusion, not identify what is already given in the argument. Also, I don't memorize argument formulas - haven't really found that to be necessary. Knowing the question types and what to look for in each type seems to be a better way to spend your time. Just my 2 cents.

KS15 · Answer

IMO, B does not look good. Just coz A and B are not quantitatively different does not mean that they are qualitatively different. Could you please explain this point?

Ella02 · Answer

B as we are talking how to it does Not help the person with brain damage bu5 with alzheimer. B helps to emphasize that both patients did not differ signifivcantly: which could ecplsin the differ3nt results

sun01 · Answer

I don't understand how b is the answer.

Argument concludes that there must be something qualitatively different about these two types of memory loss. the author arrives at this conclusion because of difference in applicability of drug in both kind of memory loss. Author stated in the premise that Mephaline did not appear to slow or reverse memory loss in people who experienced memory loss due to a brain injury.

SO, argument basically assumes that difference in cause/origin of both kind of memory losses leads to unsuitability of common drug in both the cases.

So, what information confirm this.

E can't be a weakener. Argument clearly states that There must be something qualitatively different about these two types of memory loss.
 Can any one explain?

deependra1234 · Answer

Yes What is Qualitative Difference and how is it not related to the Ages beng Different??
I was thinking between B and E but marked E as it seemed to hit the Conclusion..

Any directions experts?

Anandanwar · Answer

Hello,

Can someone please clear this confusion:
The argument talks about improvement in memory loss. 
Now take two persons, A(with memory loss x) and B(with memory loss y).
After taking a medication A can reduce the memory loss from x to x1.
After taking a medication B can reduce the memory loss from y to y1.

Now what matters is that were individual memory losses reduced or not.
It does not matter how x compares to y.

Now choice B is exploiting this point and comparing memory losses of person to person.
That should not matter to the argument. 
Similar or not, it matters whether individual memory losses were reduced or not.
This is why I rejected B.

Could you someone point out the error in the above reasoning?

Regards,
Ankit

DmitryFarberMPrep · Answer

First, take a moment to consider the type of argument we have. The author has showed evidence that a treatment worked in one group of people, but not in another. From this, they concluded that there must be a qualitative difference in the problems experienced by the two groups. To weaken an argument based on this kind of comparison-based evidence, we have to think about what other possible differences between the two groups might account for the comparison. It could be some difference in how they were treated, how the drug was administered, the lifestyles of the patients, etc. However, if the two groups are really equivalent in every meaningful way, then the only other difference than a qualitative difference in the illnesses would be a quantitative difference. It's certainly possible that beyond a certain point, memory can't be so easily restored. This is actually pretty common in medicine, but we don't have to know that. We just have to acknowledge that if one group simply had MORE memory loss, then it's possible that this difference accounted for the difference in results.

To take it to an extreme, what if one group had completely lost the affected parts of the brain? Then certainly we'd expect that they couldn't recover that function, and it would have nothing to do with the type of illness, just the extent of the damage.

VerbalBot · Answer

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Preliminary tests show that the drug known as Mephaline

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Preliminary tests show that the drug known as Mephaline

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